Black Liquor Concentration.

Reduce purchased energy consumption in chemical recovery through use of membranes

Goal and Strategy

﻿﻿Develop a more energy-efficient method to remove water from kraft pulp mill black liquor.

Reduce energy use by 23 Trillion BTU across the US Industry

Overcome barriers surrounding membrane separation technology

​R&D Needs Technologies to address the following barriers to membrane separation:

Optimal separations of water, ions, and organics

Robust membrane materials to withstand high temperature, high pH environments

Advanced high-flux membrane systems

Membrane fouling impacting system availability

Process optimization and integration with existing pulp mill systems​

Photo courtesy of Veolia Water Technologies

High-Priority ProjectsRobust Membranes to withstand high temperature, high pH environmentsPhase II - Development of RO membrane for rejection of salts, scale-up, and optimization, as well as completion of the business case based on actual performance parameters. Status: NF membranes with high rejection rate for lignin were developed in the prior phase of this work. The project is financially supported by APPTI member companies and a grant from the Renewable Bioproducts Institute at Georgia Tech. Phase II recently won Department of Energy funding as part of the RAPID Manufacturing Institute. PI: Sankar Nair, Georgia Tech

Sacrificial Coatings to provide required flux and fouling resistanceA Teledyne Scientific project to develop a commercially viable membrane-based separation system for black liquor concentration. This project leverages research and materials from a previously developed, low-cost coating process and apply the research to lower cost polymer membranes that are already used in established markets, such as municipal water treatment and water desalination. The coating will make it difficult for various foulants in the WBL to adhere to the membranes while also providing protection from harsh conditions. The coating process enables a thin 2–5 nanometer coating, both on the membrane surface and within the membrane pores, allowing the coating to chemically protect the membrane effectively and prevent fouling. Detection of a critical pressure difference across the membrane can be used as a trigger to activate a backwash for removing the loosely-bound foulants. The coating can also be periodically reformed in-situ using apparatus that is standard practice in membrane-based separations.Status: Launched in 2012; Mill pilot conducted in late 2017 PI: Vivek Mehrotra​Bench-Scale Membrane Testing with Characterization of StreamsThere are some promising commercially available membranes that might work with black liquor. They need to be tested at industrial conditions to conclusively demonstrate that a membrane-based concentration technology can produce a permeate stream suitable for combining with evaporator condensate for ultimate use in pulping washing operations. Status: Launched September 2017. As of March 2018, the test rig is operational; test procedures are in development; softwood black liquor is being tested and hardwood liquor is pending. Model synthetic liquor is being developed and tested. PI: Scott Sinquefield, Renewable Bioproducts Institute-Georgia Tech